1. Field of the Invention
The present invention relates to a pressure sensor.
2. Description of the Prior Art
Recently, a pressure sensor employing the magnetostriction effect of an amorphous magnetic alloy has been proposed (for example U.S. Pat. No. 4,938,069). In such a pressure sensor, a magnetic material having a large magnetostriction effect is fixed on a deforming part subjected to an external pressure to be detected. The permeability of the magnetic material is changed by an applied pressure, and a coil detects a permeability change caused by the applied pressure. A change of pressure is derived from a differential of the output of the coil from that of a dummy coil. In a bridge circuit including the two coils, the two coils are connected to resistances of the same impedance values of the coils, respectively. A problem of the pressure sensor of this type is that the precision of the pressure substantially worsens if the temperature departs from a standard temperature.